Inhibitors of carbohydrate-hydrolysing enzymes play an important role for the treatment of diabetes. To our knowledge, a number of inhibitors such as, 1-deoxynojirimycin, acarbose and voglibose have been identified as a result of screening of secondary metabolites up to now. In this note, we report the inhibitory effect on carbohydrate hydrolysis of ethanol extracts from more than 1400 species of plants with the aim of identifying a potential antihyperglycemic drug. Pinus densiflora bark extracts showed the highest inhibition activity against several carbohydrate-hydrolysing enzymes.